Di-(cyanoalkyl)-β-haloethanephosphonates and dithiophosphonates and use as plant growth regulators

ABSTRACT

β-Haloethanephosphonates and thio derivatives thereof of formula, ##STR1## where X signifies chlorine or bromine, 
     Y signifies oxygen or sulphur, 
     and 
     Z signifies a carboxylic acid ester or carbamoyl group, or an optionally further substituted methyl or ethyl group substituted by such a group, or signifies an acylmethyl, optionally aryl-substituted alkenyl or alkynyl, cyclic ether, e.g. tetrahydropyranyl, or optionally mono-substituted cyanomethyl group, or signifies an alkyl-, cycyloalkyl- or aryl-thio, -sulphinyl or -sulphonyl group, or an optionally further substituted methyl or ethyl group substituted by such a group, or signifies a sulphonic acid ester group, or an optionally further substituted methyl or ethyl group substituted by such a group, 
     are useful as regulators of plant growth or plant secretion, especially as stimulators of latex flow in latex-forming plants.

This is a division of application Ser. No. 803,792, filed June 6, 1977now U.S. Pat. No. 4,137,064, which in turn is a division of applicationSer. No. 612,501, filed Sept. 11, 1975, now U.S. Pat. No. 4,042,370.

The present invention relates to β-haloethanephosphonates and their thioderivatives which are useful as plant growth regulating agents.

Accordingly, the present invention provides compounds of formula I,##STR2## where X signifies chlorine or bromine,

Y signifies oxygen or sulphur, and

Z signifies a radical of formula ##STR3## wherein R signifies hydrogen,C₁ -C₆ alkyl, C₃ -C₆ cycloalkyl, unsubstituted phenyl or phenylsubstituted by one or more electron-withdrawing substituents,

R₁ signifies C₁ -C₈ alkyl, C₃ -C₆ cycloalkyl, unsubstituted phenyl orphenyl substituted by one or more electron-withdrawing substituents, and

n signifies 0, 1 or 2, or a radical or formula ##STR4## wherein R and nare as defined above, and

each of R₂ and R₃, independently, signifies hydrogen, C₁ -C₆ alkyl orphenyl, or

R₂ and R₃, together with the nitrogen atom to which each is attached,forms a heterocyclic ring of up to 7 members which optionally includes asecond hetero atom selected from oxygen, sulphur and nitrogen,

or a radical of formula ##STR5## wherein R₄ is as defined for R₁ above,or a radical of formula

    --(CH.sub.2).sub.m --CR.sub.5 ═CHR.sub.6

or

    --(CH.sub.2).sub.m --C.tbd.C--R.sub.7,

wherein

each of R₅, R₆ and R₇ signifies hydrogen, C₁ -C₈ alkyl, unsubstitutedphenyl or phenyl substituted by one or more electron-withdrawingsubstituents, and

m signifies 0, 1 or 2,

or a radical of formula ##STR6## wherein p signifies 1, 2, 3 or 4, or aradical of formula ##STR7## wherein R is as defined above, or a radicalof formula ##STR8## wherein R and n are as defined above,

r signifies 0, 1 or 2, and

R₈ is as defined for R₁ above,

or a radical of formula ##STR9## wherein R and n are as defined above,and

R₉ is as defined for R₈ above.

In the above definition, it is to be understood that any alkyl group maybe straight or branched chain when containing 3 or more carbon atoms.Preferred examples of electron-withdrawing substituents for anysubstituted phenyl group are halogen, cyano, carboxy, C₂ -C₈alkoxycarbonyl, C₂ -C₈ alkylcarbamoyl, trihaloalkyl, C₁ -C₈alkylsulphinyl unsubstituted phenylsulphinyl, phenylsulphinylsubstituted by a methyl or ethyl group, or two methyl groups, C₁ -C₈alkylsulphonyl, unsubstituted phenylsulphonyl, phenylsulphonylsubstituted by a methyl or ethyl group or two methyl groups, and nitro.By halogen is meant fluorine, chlorine or bromine. Preferredheterocyclic rings signified by NR₂ R₃ are pyrrolidino, piperidino andmorpholino.

Preferably in the compounds of formula I, X is chlorine and,independently, Y is preferably oxygen. Independently from the values ofX and Y, Z is preferably a radical of formula ##STR10##

When Z is ##STR11## n is preferably 0 and, independently, R₁ ispreferably alkyl. In particular the preferred significance of Z in thiscase is butoxycarbonyl, more specifically, n-butoxycarbonyl.

When Z is --(CH₂)_(m) C═C--R₇, independently m is preferably 1 and R₇hydrogen. In particular the preferred significance of Z in this case ispropargyl.

When Z is ##STR12## CN, R is preferably hydrogen.

Particularly preferred compounds of formula I aredi-(n-butoxycarbonylmethyl) 2-chloroethanephosphonate, di-propargyl2-chloroethanephosphonate and di-(2-cyanoethyl)2-chloroethanephosphonate.

The present invention further provides a process for the production of acompound of formula I, as defined above, which comprises reacting acompound of formula II, ##STR13## where X is as defined above, and

L signifies chlorine or bromine,

with a compound of formula III,

    MY--CH.sub.2 Z                                             III

where Y and Z are as defined above, and

M signifies hydrogen or the equivalent of a cation, in such a proportionthat both chlorine or bromine atoms signified by (L)₂ in the compound offormula II are replaced by --Y--CH₂ --Z radicals, and with the provisothat when M is hydrogen, the reaction is effected in the presence of anacid acceptor.

The preferred cations for M are sodium and potassium.

The production is preferably effected by adding the compound of formulaIII to a stirred solution or suspension of the compound of formula II ina suitable anhydrous solvent or diluent, e.g. a hydrocarbon such asbenzene or toluene, a halogenated hydrocarbon such as chloroform orchlorobenzene, a ketone such as acetone or butan-2-one, a nitrile suchas acetonitrile, an ester such as an ester of acetic acid, an amide suchas dimethyl formamide, or an ether such as dioxan, tetrahydrofuran ordiethyl ether, of which ether solvents the latter two are preferred, orin a mixture of solvents, and continuing stirring, for example over aperiod of up to 3 days, optionally with heating, for example in therange 25° to 40° C. The product may thereafter be isolated by aconventional technique.

When an acid acceptor is used in the reaction medium, this may be atertiary organic base such as triethylamine, N-methylmorpholine,methyl-di-isopropylamine or pyridine, of which pyridine is preferred.

The reaction is generally exothermic, and appropriate care must be takenin its control.

The compounds of formula II used as intermediates are known, whereasonly some of the compounds of formula III are known, the remainder beingproducible by known methods or analogously to such known methods.

The compounds of the present invention are useful as plant growthregulating agents, in particular plant growth stimulating agents. Theyare especially useful in stimulating plant secretion, e.g. of latex,plant gums, resins and useful terpenoid constituents.

Of especial interest is the effect of the compounds of the presentinvention in stimulating latex flow in latex forming plants, e.g. inHevea brasiliensis. The three aforementioned specific compounds areparticularly notable in this regard.

Accordingly the present invention further provides a method ofregulating the growth of plants or regulating plant secretion byapplying to the plants an effective amount of a compound of formula I,as defined above. The method of the invention is especially preferredfor stimulating latex flow in latex-forming plants, preferably Heveabrasiliensis.

The compounds are generally applied as a formulation in a suitable plantgrowth regulator carrier, diluent and/or adjuvant in liquid, semi-liquidor solid form, the compound preferably being blended intimately in eachcase with the appropriate formulation medium, and such formulations arealso provided by the present invention. Examples of such formulationsare as follows, the percentages being by weight:

(a) For di-(n-butoxycarbonylmethyl) 2-chloroethane-phosphonate as thecompound of formula I:

10% compound, 13% xylene and 77% coconut oil blended intimately

15% compound, 18% xylene and 67% coconut oil blended intimately

22% compound, 25% xylene and 53% coconut oil blended intimately.

(b) For di-propargyl 2-chloroethane-phosphonate as the compound offormula I:

10% compound, 13% xylene and 77% coconut oil blended intimately

22% compound, 25% xylene and 53% coconut oil blended intimately.

(c) For di-(2-cyanoethyl) 2-chloroethane-phosphonate as the compound offormula I:

10% compound, 47% cyclohexanone and 43% coconut oil blended intimately.

15% compound, 51% cyclohexanone and 34% coconut oil blended intimately.

22% compound, 55% cyclohexanone and 23% coconut oil blended intimately.

The effect of the compounds of the invention in stimulating latex flowin latex forming plants is illustrated in the following test: A fieldtrial was conducted on Hevea brasiliensis trees (Indian clone 331) ofabout 15 years old in the state of Karala, India. The period of the testcoincided with a normal tapping season. i.e. when rainfall had set infollowing a seasonal dry period.

On each tree a surface layer of bark, immediately below and parallelwith the existing tapping cut, as a strip of the width corresponding toabout 8 weeks tapping consumption, was carefully abraded and removed.The penetration was just sufficient to expose but not to pierce the redcambium. To the exposed strip of red cambium 2.5 ml of the 10%formulation of di-(2-cyanoethyl) 2-chloroethane-phosphonate detailed in(a) above was evenly applied with a brush.

During the ensuing approx. 8 weeks period the treated exposed bark stripwas removed in equal proportions every 2-3 days according to normaltapping practice. The latex produced was collected and its weightmeasured. Determination of the dry rubber content was also determined bya conventional method, and it was found as a result that there was a100- to 250-fold increase in yield per tree compared to the yield fromuntreated trees of the same age and clone which were included in thetrial for comparison purposes.

For use in latex flow stimulation the compounds of the invention arepreferably applied in a jelly formulation, which consists of thecompound of formula I dissolved in an organic solvent, this solutionthen being thickened by means of a thickening agent until the desiredjelly constituency has been achieved. The organic solvent may consistentirely of a single solvent, e.g. an aromatic or aliphatic solvent, ormay consist of a mixture of solvents. It is often advantageous toinclude a polar solvent such as dimethylsulphoxide or dimethylformamidein a mixed solvent to aid dissolution of the compound. An example of asuitable aromatic solvent is xylene, and of a suitable thickening agentis hydroxyethyl cellulose.

In the following example of a suitable jelly formulation for use instimulating latex flow, the percentages are by weight:

10% of a compound of formula I dissolved in 20% of an aromatic solvent,e.g. xylene, and 67% of a polar solvent, e.g. dimethylsulphoxide ordimethylformamide to which has been added 3% of hydroxyethyl cellulosewith vigorous stirring until thickening has developed sufficiently toachieve the desired jelly constituency.

The amount of compound of formula I applied to rubber trees, e.g. Heveabrasiliensis, will vary depending on the compound employed, the mode ofapplication, the species and size of tree and the prevailing climaticconditions, amongst other factors. However, satisfactory results aregenerally obtained when the compound of formula I is applied at the rateof 0.2 to 0.8 g per tree. When applied in a 10% jelly formulation, thiscorresponds to 2 to 8 g of jelly formulation containing 10% w/w ofcompound of formula I per tree.

The following Examples illustrate the production of the compounds of theinvention. Temperatures are in degrees Centigrade.

EXAMPLE 1: Di(2-cyanoethyl) 2-chloroethane-phosphonate

To a solution of 45.5 g (0.25 mol) of 2-chloroethane phosphonic aciddichloride in 1200 ml of absolute diethyl ether are added 35.5 g (0.5mol) of 3-hydroxypropionitrile. The solution is observed to becomecloudy. At room temperature 38.5 g (0.488 mol) of pyridine are addeddropwise, during which the temperature increases to 30° andcrystallisation occurs. The mixture is stirred for 60 hours at 35° afterwhich the ethereal solution is decanted.

Subsequently the hydrochloride residue is dissolved in 100 ml of waterand the resulting solution is subjected to a fluid extraction withdiethyl ether over a period of 3 days. Methylene chloride is then addedto effect the solution of the separated oil and the whole is dried overanhydrous sodium sulphate and subsequently evaporated. Finally theresidual oil is evaporated in a rotary evaporator for 3 hours at 45°,the product having the following characterisation data:

Analysis: C₈ H₁₂ ClN₂ O₃ P: Mol weight: 250. Calc.--C 38.3%, H 4.8%, Cl14.1%, N 11.2%, P 12.4%, Found--C 39.0%, H 5.2%, Cl 14.0%, N 11.1%, P11.9%.

n_(D) =1.475

NMR (δ, ppm) in CDCl₃ : CH₂ with P multiplet 2.17-2.73; CH₂ with Cl:3.81 (5 lines). Ester-CH₂ with CN at 2.82 (triplet) and ester-CH₂ with Oat about 4.36 (multiplet).

EXAMPLE 2: Di-(ethoxycarbonylethyl) 2-chloroethanephosphonate

To a solution of 9.1 g (0.05 mol) of 2-chloroethane phosphonic aciddichloride and 11.5 g (0.098 mol) of 3-hydroxypropionic acid ethylesterin 200 ml of absolute diethyl ether are added dropwise with stirring7.75 g (0.098 mol) of pyridine in 20 ml of absolute diethyl ether atroom temperature. During the addition the hydrochloride formedcrystallises out and the temperature increases to 35°. Stirring iscontinued for 60 hours at room temperature.

The hydrochloride salt is collected by filtration and the etherealfiltrate is evaporated. The residue is further dried by rotation underhigh vacuum at 40° over a period of 3 hours, the product having thefollowing characterisation data:

n_(D) =1.459

Analysis: C₁₂ H₂₂ ClO₇ P: Mol weight: 344.7 Calc.--C 41.8%, H 6.4%, Cl10.3%, P 9.0%, Found--C 41.6%, H 6.6%, Cl 10.4%, P 10.0%.

NMR (δ, ppm) in CDCl₃ : CH₂ with P as multiplet between 2.05 and about2.70; CH₂ with Cl as multiplet around 3.7. Ester-CH₂ with CO at 2.68(triplet), ##STR14## and --OCH₂ CH₃ as multiplet around 4.3.

CH₃ of the ethyl group as triplet at 1.28.

EXAMPLE 3: Di-(2-ethoxycarbonyl-2-phenylethyl) 2-chloroethanephosphate

To a solution of 19.4 g (0.1 mol) of 2-phenyl-3-hydroxypropionic acidethylester and 9.1 g (0.05 mol) of 2-chloroethane phosphonic aciddichloride in 100 ml of absolute diethyl ether are added dropwise withstirring 7.9 g (0.1 mol) of absolute pyridine in 50 ml of absolutediethyl ether at room temperature, during which the the temperatureincreases to 30° and crystallisation occurs. Stirring is continued for35 hours at 25° after which the crystals are removed by filtration andthe ethereal filtrate is washed with water to neutrality, dried andconcentrated. The resulting oil is further evaporated in a rotaryevaporator at 25° for 2 hours yielding a product with the followingcharacterisation data:

Analysis: C₂₄ H₃₀ ClO₇ P: Mol weight: 496.5. Calc.--C 58.0%, H 6.1%, Cl7.1%, P 6.2%, Found--C 57.7%, H 6.3%, Cl 7.2%, P 5.8%.

NMR (δ, ppm) in CDCl₃ : ester-CH₃ at 1.2 (triplet), ester-CH₂ at 4.16(quartet). CH₂ with P as multiplet between 1.8 and 2.55. Remainingaliphatic protons as superimposed multiplets of 3.3-4.7.

Aromatic protons: 7.30 (singlet).

n_(D) ²⁰° =1.5186

EXAMPLE 4: Di-(2-ethoxycarbonylethyl) 2-chloroethanedithiophosphonate

To a solution of 9.1 g (0.05 mol) of 2-chloroethane phosphonic aciddichloride and 13.4 g (0.1 mol) of 2-mercaptopropionic acid ethylesterin 100 ml of absolute diethyl ether are added 7.9 g (0.1 mol) ofabsolute pyridine in 50 ml of absolute diethyl ether with stirring.During the reaction white crystals are produced. Stirring is continuedfor 15 hours at 40°.

To the reaction mixture are then added 100 ml of water, and the aqueoussolution is extracted with 5 50 ml amounts of diethyl ether. Theethereal extracts are washed with water to neutrality, dried andconcentrated by evaporation.

The resulting colourless oil is dissolved in methylene chloride and thesolution is passed down a silica gel column after which the productisolated from the solution is chromatographed with diethyl ether. Theproduct is a yellow oil with the following characterisation data.

Analysis: C₁₂ H₂₂ ClO₅ PS₂ : Mol weight: 376.5. Calc.--C 38.2%, H 5.9%,Cl 9.4%, P 8.2%, S 17.0%, Found--C 39.3%, H 6.2%, Cl 9.2%, P 7.9%, S17.5%.

NMR (δ, ppm) in CDCl₃ : ester-CH₃ as triplet at 1.26; CH₂ with S and CH₂with CO as partially overlapping multiplets between 2.5 and 3.37. CH₂with Cl between 3.43 and 3.93 (multiplet). Ester-CH₂ with O as quartetat 4.19

n_(D) ²⁰° =1.520

EXAMPLE 5: Di-[2-(N,N-diethylcarbamoyl)ethyl]2-chloroethanephosphonate

To a solution of 14.5 g (0.1 mol) of N,N-diethyl-3-hydroxypropionamide(produced according to JACS 73, 3168-71 (1951)) and 7.9 g (0.1 mol) ofabosolute pyridine in 100 ml of tetrahydrofuran are added dropwise 9.1 g(0.05 mol) of 2-chloroethane phosphonic acid dichloride with stirring.During the addition the temperature increases to 40° and thereafterstirring is continued for a further 15 hours at 25°.

The reaction mixture is evaporated and the residue is dissolved inmethylene chloride, the solution then being washed with water. Afterseparation of the aqueous phase the latter is extracted 3 times with 50ml of methylene chloride. The combined methylene chloride extracts arewashed with water until the aqueous phase attains a pH of 5-6. Themethylene chloride solution is dried and then concentrated byevaporation, a yellow oil being produced as a residue. This is subjectedto chromatography on neutral aluminium oxide (Woelm: column size 20×4cm) with ethyl acetate, a colourless oil being finally obtained, withthe following characterisation data:

Analysis: C₁₆ H₃₂ ClN₂ O₅ P: Mol weight: 398.5. Calc.--C 48.2%, H 8.1%,N 7.0%, P 7.8%, Found--C 48.3%, H 8.0%, N 6.9%, P 7.5%.

NMR (δ, ppm) in CDCl₃ : amide-CH₃ multiplet 0.95-1.35; CH₂ with P about2.0-2.5. CH₂ with CO 2.5-2.85; CH₂ with N 3.2-3.5; CH₂ with Cl about3.4-3.9 (partially covered); CH₂ with O 4.0-4.55 (all multiplets).

EXAMPLE 6: Di-[2-(N-n-butylcarbamoyl)ethyl]2-chloroethanephosphonate

To a solution of 14.5 g (0.1 mol) of N-butyl 3-hydroxypropionamide(produced as described in JACS 73, 3168-71 (1951)) and 9.1 g (0.05 mol)of 2-chloroethane phosphonic acid dichloride in 100 ml of absolutetetrahydrofuran are added dropwise 7.9 g (0.1 mol) of absolute pyridinewith stirring. Upon the addition the solution begins to boil and an oilyprecipitate appears. Stirring is continued for a further 60 hours at25°.

The mixture is evaporated and the oily residue is dissolved inchloroform. This solution is washed with water and the aqueous phase isextracted with 3 50 ml portions of chloroform. The combined chloroformextracts are washed with water until the aqueous phase reaches a pH of 5and then the chloroform solution is dried and concentrated byevaporation. Produced is a yellow oil, which is subjected tochromatography on silica gel (column size 25×3.5 cm) firstly with ethylacetate and subsequently with methanol, resulting in a yellow oil as themain fraction extracted with methanol. This fraction crystallises onstanding and is submitted to recrystallisation with a mixture ofmethylene chloride and diethyl ether, affording white crystals, m.p.68°-72°. Further characterisation data are as follows:

Analysis: C₁₆ H₃₂ ClN₂ O₅ P: Mol weight: 398.5. Calc.--C 48.2%, H 8.1%,Cl 8.9%, N 7.0%, P 7.8%, Found--C 48.2%, H 8.3%, Cl 9.4%, N 6.5%, P8.4%.

NMR (δ, ppm) in CDCl₃ : butyl-CH₃ as multiplet around 0.95. The adjacent4 butyl protons between 1.1 and 1.65 (multiplet). CH₂ with P 2.0-about2.5. CH₂ with CO as triplet at 2.56. CH₂ with NH as multiplet between3.05 and 3.45. CH₂ with Cl at 3.55-3.95 and CH₂ with O at 4.18-4.53(multiplet). NH-protons as broad signal at 6.54.

EXAMPLE 7: Di-(2-ethylthioethyl)2-chloroethanephosphonate

To a solution of 18.1 g (0.1 mol) of 2-chloroethane phosphonic aciddichloride in 150 ml of absolute ether is added dropwise with stirring asolution of 21.2 g (0.2 mol) of hydroxyethyl ethyl sulphide and 15.8 gof absolute pyridine in 100 ml of absolute ether at room temperature,during which the temperature increases to 35° and crystallisationoccurs. Stirring is continued for a further 14 hours at 25° after whichthe crystals are removed by filtration and the ethereal filtrate iswashed to neutrality with 5% hydrogen carbonate solution and water. Itis dried and evaporated and further dried by rotation under high vacuumfor 2 hours. A yellow oil is obtained having the followingcharacterisation data:

Analysis: C₁₀ H₂₂ ClO₃ PS₂ Mol weight: 320.8 Calc.--C 37.4%, H 6.9%, Cl11.1%, P 9.7%, S 20.0%, Found--C 37.4%, H 6.7%, Cl 11.6%, P 8.8%, S19.5%.

n_(D) ²⁰° =1.5079

NMR (δ, ppm) in CDCl₃ : ester-CH₃ as triplet at 1.27; CH₂ with P at2.0-about 2.5 and CH₂ with S at 2.4-3.0 (multiplet). CH₂ with Cl between3.5 and about 3.9 and CH₂ with O at 4.0-4.4 (multiplet).

n_(D) ²⁰°. 1.5079

EXAMPLE 8: Di-allyl 2-chloroethanephosphonate

To a solution of 11.6 g (0.2 mol) of allyl alcohol and 18.1 g (0.1 mol)of 2-chloroethane phosphonic acid dichloride in 150 ml of absolute etherare added dropwise with stirring 15.8 g (0.2 mol) of pyridine. When theexothermic reaction is complete, stirring is continued for 15 hours at40° after which the precipitated hydrochloride is removed by filtrationand the ethereal filtrate washed to neutrality with water, dried andthen evaporated. It is further dried by rotation under high vacuum overa period of 2 hours at 25°. A yellowish oil is obtained having thefollowing characterisation data:

Analysis: C₈ H₁₄ ClO₃ P. Mol weight: 224.6. Calc.--C 42.7%, H 6.3%, Cl15.9%, P 13.9%. Found--C 42.3%, H 6.5%, Cl 17.9%, P 14.2%.

n_(D) ²⁰° =1.4662

NMR (δ, ppm) in CDCl₃ : CH₂ with P as multiplet at 2.0-2.6; CH₂ with Clas multiplet at 3.5-4.0. Allyl protons as multiplets about 4.5.Resultant vinyl protons 5.1-5.5 and vinyl protons with CH₂ between 5.6and 6.2 (multiplet).

EXAMPLE 9: Di-propargyl 2-chloroethanephosphonate

To a solution of 11.9 g (0.2 mol) of propargyl alcohol and 18.1 g (0.1mol) of 2-chloroethane phosphonic acid dichloride in 150 ml of absolutediethyl ether are added with stirring 15.8 g (0.2 mol) of absolutepyridine, whereupon an exothermic reaction occurs. Stirring is continuedfor a further 15 hours at 40°.

The precipitated hydrochloride is removed from the reaction mixture byfiltration, and the ethereal filtrate is washed to neutrality withwater, dried and evaporated. After further drying of the residue underhigh vacuum for 2 hours at 25° a yellow oil is obtained as the producthaving the following characterisation data:

n_(D) ²⁰° =1.4839

Analysis: C₈ H₁₀ ClO₃ P. Mol weight: 220.6 Calc.--C 43.6%, H 4.5%, Cl16.1%, P 14.1%. Found--C 43.2%, H 4.6%, Cl 16.2%, P 13.5%.

NMR (δ, ppm) in CDCl₃ : CH₂ with P as multiplet between 2.1 and 2.6.Acetylene proton at 2.69. CH₂ with Cl as multiplet between 3.52 and 4.0.Ester--CH₂ with O between 4.6 and 4.8 (multiplet).

EXAMPLE 10: Di-(n-butoxycarbonylmethyl) 2-chloroethanephosphonate

To a solution of 13.2 g (0.1 mol) of glycolic acid butylester and 9.1 g(0.05 mol) of chloroethane phosphonic acid dichloride in 100 ml ofabsolute ether are added with stirring a solution of 7.9 g (0.1 mol) ofabsolute pyridine in 50 ml of absolute diethyl ether. A whiteprecipitate results and the reaction mixture begins to boil. Stirring iscontinued for a further 15 hours at 25° and the precipitatedhydrochloride is removed by filtration. The ethereal filtrate isextracted with 2 50 ml portions of 2 N hydrochloric acid, followed by 250 ml portions of 2 N sodium hydroxide solution and then washed toneutrality with water, dried and concentrated by evaporation. Furtherevaporation of the concentrate under high vacuum in a rotary evaporatorfor 2 hours at 25° results in a colourless oil having the followingcharacterisation data:

n_(D) ²⁰° =1.4525

Analysis: C₁₄ H₂₆ ClO₇ P. Mol weight: 373.8. Calc.--C 45.1%, H 7.0%, Cl9.5%, P 8.3%. Found--C 44.6%, H 7.0%, Cl 9.5%, P 8.3%.

NMR (δ, ppm) in CDCl₃ : butyl protons as wide multiplets at 0.8-1.8.Butyl--CH₂ with O as multiplet at about 4.2. CH₂ with P between 2.15 and2.85 and CH₂ with Cl between 3.6 and 4.1 (multiplets). Glycolicacid--CH₂ as doublet at 4.68 with J_(PH) =12 Hz.

EXAMPLE 11: Di-(tetrahydropyran-2-ylmethyl) 2-chloroethanephosphonate

To a solution of 11.6 g (0.1 mol) of 2-hydroxymethyltetrahydropyran and9.1 g (0.05 mol) of 2-chloroethane phosphonic acid dichloride in 200 mlof absolute diethyl ether is added a solution of 7.9 g (0.1 mol) ofabsolute pyridine in 50 ml of absolute diethyl ether with stirring.During the addition a white precipitate is formed. Stirring is continuedfor a further 15 hours at 35°, after which the precipitate is removed byfiltration and the ethereal filtrate is washed to neutrality withhydrogen carbonate solution, followed by water. The ethereal solution isconcentrated by evaporation and further evaporated in high vacuum in arotary evaporator for 4 hours at 25°, to yield a product with thefollowing characterisation data:

n_(D) ²⁰° =1.4810

Analysis: C₁₄ H₂₆ ClO₅ P. Mol weight: 340.9. Calc. C 49.3%, H 7.7%, Cl10.7%, P 9.1%, Found C 49.4%, H 7.7%, Cl 10.4%, P 9.3%.

NMR (δ, ppm) in CDCl₃ : methylene protons of the tetrahydropyran ring,which are not adjacent to the O, as multiplets between 1.2 and about2.0. CH₂ with P as multiplet at 2.1-2.7. Remaining protons asoverlapping multiplets between 3.1 and 4.2.

EXAMPLE 12: Di-(3-ethoxycarbonyl-n-propyl) 2-chloroethanephosphonate

To a solution of 13.2 g of ethyl 4-hydroxybutyrate (produced asdescribed in J. Org. Chem. 31, 487 (1966)) and 9.1 g (0.05 mol) of2-chloroethane phosphonic acid dichloride in 100 ml of absolute diethylether is added a solution of 7.9 g (0.1 mol) of absolute pyridine in 50ml of absolute diethyl ether. During the addition white crystals areprecipitated and the temperature increases to 35°. Stirring is continuedfor a further 20 hours at 40°.

After the reaction mixture has been cooled to room temperature thecrystals are removed by filtration and the ethereal filtrate is washedto neutrality with hydrogen carbonate solution followed by water. Theethereal solution is concentrated by evaporation and further evaporatedin high vacuum for 24 hours at 25°, resulting in a clear yellow oil withthe following characterisation data:

n_(D) ²⁰° =1.458

Analysis: C₁₄ H₂₆ ClO₇ P. Mol weight: 372.8

Calc.--C 45.1%, H 7.0%, Cl 9.5%, P 8.3%. Found--C 44.8%, H 6.9%, Cl9.8%, P 8.1%.

NMR (δ, ppm) in CDCl₃ : ester CH₃ as triplet at 1.27. The protons of thetwo CH₂ groups which are adjacent to the CO group, as well as the CH₂with P appear as superimposed multiplets between 1.75 and 2.65. CH₂ withCl 3.52-3.87. All CH₂ with O as superimposed multiplets between 3.96 and4.48.

What is claimed is:
 1. A compound of the formula: ##STR15## wherein X ischlorine or bromine,Y is oxygen or sulfur, and R is hydrogen, C₁ -C₆alkyl, C₃ -C₆ cycloalkyl, unsubstituted phenyl or phenyl substituted byone or more members selected from the group consisting of fluoro,chloro, bromo, cyano, carboxy, C₂ -C₈ alkoxycarbonyl, C₂ -C₈alkylcarbamoyl, trihaloalkyl, C₁ -C₈ alkylsulphinyl, unsubstitutedphenylsulphinyl, phenylsulphinyl substituted by a methyl or ethyl groupor two methyl groups, C₁ -C₈ alkylsulphonyl, unsubstitutedphenylsulphonyl, phenylsulphonyl substituted by a methyl or ethyl groupor two methyl groups, and nitro.
 2. A compound according to claim 1,which is di-(2-cyanoethyl) 2-chloroethanephosphonate.
 3. A method ofregulating the growth of plants or regulating plant secretion byapplying to the plants a plant growth or secretion regulating effectiveamount of a compound according to claim
 1. 4. A method according toclaim 3, for stimulating latex flow in latex-forming plants by theapplication to the plants of a latex flow stimulating effective amountof the compound.
 5. A method according to claim 4, in which thelatex-forming plants are Hevea brasiliensis.
 6. A method according toclaim 4, in which the compound is applied to latex-forming plants in anamount between 0.2 to 0.8 g per tree.
 7. A plant growth or plantsecretion regulating formulation comprising a plant growth or secretionregulating effective amount of a compound according to claim 1 inassociation with a plant growth regulator carrier, diluent and/oradjuvant.
 8. A formulation according to claim 7 in which the compounddissolved in an organic solvent and sufficient thickening agent torender the formulation of a jelly constituency.
 9. A formulationaccording to claim 8, in which the organic solvent comprises xylene andeither dimethyl sulphide or dimethyl formamide, and the thickening agentcomprises hydroxyethyl cellulose.